Shader "Unlit/ChessboardShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _SquareSize ("Square Size", Range(1, 100)) = 5
        _Color1 ("Color 1", Color) = (0,0,0,1)
        _Color2 ("Color 2", Color) = (1,1,1,1)
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            float _SquareSize;
            float4 _Color1;
            float4 _Color2;
            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }
            
            fixed4 _GridColor;
            fixed4 frag (v2f i) : SV_Target
            {
              float2 uv = i.uv;
                int row = int(uv.y * _SquareSize);
                int col = int(uv.x * _SquareSize);
                float4 color = (row + col) % 2 ==1  ? _Color1 : _Color2;
                return color;
            }
            ENDCG
        }
    }
}
